Mastitis is an inflammation of the mammary gland. Bovine mastitis is the most common and most costly disease affecting dairy herds. Some estimates suggest at least half of the dairy animal population having some degree or form of mastitis. This condition results in lowered milk yield and reduced milk quality. Economic loss to mastitis in the U.S. is estimated at about $1.8 billion or approximately 10% of total milk sales with about two-thirds of this loss due to reduced milk production from infected cows. In dairy cattle, mastitis typically results from microorganisms; usually bacteria, that invade the udder, multiply in the milk producing tissues, and synthesize toxins, a by-product of bacterial metabolism. The characteristic features of inflammation are swelling, heat, redness, pain and disturbed function.
While the animal immune system can fight intramammary infections, many chronic infections remain sub-clinical (asymptomatic) and undetected unless diagnosed by laboratory testing. Sub-clinical mastitis can result in a reservoir of microorganisms, which can lead to the infection of other animals within the herd. More than 80 species of microorganisms have been identified as causal agents, although approximately 95% of mastitis is caused by four pathogens: Staphylococcus aureus, Streptococcus agalactiae, Streptococcus dysagalactiae, and Streptococcus uberis. Mastitis causing pathogens fall into two categories namely contagious and environmental. Contagious bacteria, such as Streptococcus agalactiae and Staphylococcus aureus, primarily colonize host tissue sites such as mammary glands, teat canals, teat skin lesions etc. and are spread from one infected cow to another during the milking process. Environmental bacteria, often streptococci, enterocci and coliform organisms, are commonly present within the cow's surroundings from sources such as cow feces, soil, plant material, bedding or water, and infect by casual opportunistic contact with an animal. This distinction, although not exclusive, is of practical importance because different dairy herd maintenance measures are needed for the different groups of microorganisms. In all bovine mastitis cases, whatever the causal microorganism, the route of transmission of the invading pathogen into the inner gland of the udder is through the teat orifice and teat canal.
Management of dairy herds focuses attention on treatment of both established mastitis and on prevention of new intramammary infections. Therapy and hygiene are two fundamental components of an effective mastitis control program. Each is applied in concert, and each operates independently. The primary effect of therapy is to eliminate established infections, whereas, hygiene reduces the incidence of new infection by interrupting transmission vectors. A non-exhaustive list of ancillary factors which may be employed for the elimination and prevention of mastitis, include, post-lactation antibiotic infusion into the udder (e.g., dry cow treatment); and, post-milking teat antisepsis or “teat dipping” during lactation.
Researchers agree, and an abundance of published evidence supports the concept, that dipping teats into an effective antimicrobial solution immediately after each milking is the single most effective procedure for decreasing new intramammary infections in lactating cows. Between 1955 to 1970, Dodd and co-workers conducted extensive epidemiologic investigations in commercial dairy herds (F. K. Neave, F. H. Dodd, and R. G. Kingwell, 1966, “A Method of Controlling Udder Disease”, Vet. Rec. 78:521; F. K. Neave, F. H. Dodd, R. G. Kingwell and D. R. Westgarth, 1969, “Control of Mastitis in the Dairy Herd by Hygiene and Management”, J. Dairy Sci. 52:696; F. H. Dodd, D. R. Westgarth, F. K. Neave and R. G. Kingwill, 1969, “Mastitis—The Strategy of Control”, J. Dairy Sci. 52:689; and F. H. Dodd, and F. K. Neave, 1970, “Mastitis Control”, Proceedings, Nat'l. Inst. Res. Dairying, pp. 21–60). From this work, they developed the conceptual basis for modern mastitis control methods of which teat dipping is an integral component. The efficacy and value of teat dipping has since been confirmed in dozens of field trials, and it is now accepted that an effective teat dip can reduce the incidence of new intramammary infections at least 50% and often up to 90%.
To reduce mastitis, commercial teat dips have been developed containing a variety of antimicrobial agents including iodophors, quaternary ammonium compounds, chlorhexidine salts, chlorine release compounds (e.g. alkali hypochlorites), oxidizing compounds (e.g. hydrogen peroxide, peracids), protonated carboxylic acids (e.g. octanoic, nonanoic, decanoic, acids), acid anionics (e.g. alkylaryl sulfonic acids), and chlorine dioxide (from chlorite). These agents, which have varying degrees of effectiveness, limit the transmission of mastitis by reducing pathogen populations on the teat. Teat dips, can also be divided into two broad classifications. The Class I type are antimicrobial and are applied to kill microorganisms already present in the teat canal or on the surface of the teat skin By design, their microbiological effect is immediate and they primarily target the contagious organisms that are vectored between animals during the pre-milking, milking and post-milking process. The Class II type teat dip, often referred to as a “teat sealer,” is a film-forming or coating composition which may or may not be antimicrobial; and, functions by developing a residual protective barrier on the teat thus providing prophylaxis by sealing the teat orifice from environmental contamination. The film, which forms on the surface of the teat, serves as a physical barrier through which mastitis causing pathogens cannot penetrate during the intermilking period.
General disclosures of teat dip technology are shown in, for example, “Current Concepts of Bovine Mastitis.” 1996, Fourth Ed. National Mastitis Council, Madison Wis.; P. A. Murdough and J. W. Pankey, 1993. “Evaluation of 57 Teat Sanitizers Using Excised Cow Teats”, J. Dairy Sci. 76:2033–2038; J. W. Pankey et al., 1984, “Uptake on Post-milking Teat Antiseptics”, J. Dairy Sci. 67:1336–1353; R. J. Farnsworth, 1980, “Role of Teat Dips in Mastitis Control”, J. Am. Vet. Med. Assoc. 76:1116–1118; W. N. Philpot, 1979, “Control of Mastitis by Hygiene and Therapy”, J. Dairy Sci. 62:168–176; W. N. Philpot and J. W. Pankey, 1978, “Hygiene in the Prevention of Udder Infections V. Efficacy of Teat Dips Under Experimental Exposure to Mastitis Pathogens”, J. Dairy Sci. 61:956–963; R. P. Natzke, 1977, “Role of Teat Dips and Hygiene is Mastitis Control”, J. Amer. Vet. Med. Assoc. 170:1196–1198; W. N. Philpot and J. W. Pankey, 1975, “Hygiene in the Prevention of Udder Infections. III. Effectiveness of 59 Teat Dips for Reducing Bacterial Populations on Teat Skin”, J. Dairy Sci. 58:209–216; R. J. Eberhart and J. M. Buckalew, 1972, “Evaluation of a Hygiene and Dry Period Therapy Program for Mastitis Control”, J. Dairy Sci. 55:1683–1691; W. D. Schultze and J. W. Smith, 1972, “Effectiveness of Postmilking Teat Dips”, J. Dairy Sci. 55:426–431; D. P. Wesen and L. H. Schultz, 1970, “Effectiveness of a Post-Milking Teat Dip in Preventing New Udder Infections”, J. Dairy Sci. 53:1391–1403; and British Pat. No. 1,144,637 (Kelco Chemicals Ltd.), published Mar. 5, 1969.
Typical disclosures of intermilking or protective (barrier-type) film-forming teat dips or teat “sealers” can be found in Akers et. al., U.S. Pat. No. 3,066,071, issued Nov. 27, 1962; Kraus, U.S. Pat. No. 3,222,252, issued Dec. 7, 1965 (but, see Philpot et. al., J. Dairy Science 58:205–216); Coughman and Brown, U.S. Pat. No. 3,993,777, issued Nov. 23, 1976; Pugliese, U.S. Pat. No. 4,049,830, issued Sep. 20, 1977; and Andrews et al., U.S. Pat. No. 4,113,854, issued Sep. 12, 1978. One disadvantage of many such film-forming agents is their tendency to form a “hard” film, which is tenacious and often difficult to remove.
There is a growing acceptance among academics, veterinarians and dairy herd management that proactive maintenance of teat health and skin condition is an integral part of a complete program for the prevention, control and remedial correction of mastitis in mild producing animals. A growing number of publications support this (see for example, M. D. McKinzie and T. C. Hemling, 1995, “The Effect of Teat Skin Condition on Milk Yield and Milkout Time”, National Mastitis Council Proceedings, pp 160–163; L. K. Fox, 1992, “Colonization of Staphylococcus Aureus On Chapped Skin: Effect of Iodine and Chlorhexidine Postmilking Teat Disinfectants”, J. Dairy Sci. 75:66; and J J Goldbert et al., 1994, “Evaluation of Teat Conditioning Qualities of Postmilking Teat Dips”, National Mastitis Council technology transfer Session, Orlando, Fla. The assertion is that a healthy milk delivery organ can naturally retard and more readily withstand the adverse affects of infection.
Although many teat dip products are available, and there remains a continuing need for new and effective teat dip compositions having immediate and long lasting antimicrobial effect against a wide spectrum of mastitis causing organisms; there is need for such antimicrobial compositions which additionally provide superior skin conditioning and health maintenance functions.
Additionally, many teat dip products are not conducive for use in cold environment conditions. For example, many teat dip compositions include a large amount of water, and can freeze in cold environments. Such compositions can freeze on the teats, and cause irritation, chapping and frostbite, and such conditions can enhance the incidence of mastitis caused by opportunistic invasive microorganisms.
Thus, although many teat dip products are available, there is a continuing need for new and effective teat dip compositions having immediate and long lasting antimicrobial effect against a wide spectrum of mastitis causing organisms that are formulated for use in cold environments.